Resistor Value Calculator
Calculate resistor values in series and parallel circuits, voltage dividers, and solve Ohm's law problems with our comprehensive resistor calculator.
Resistor Calculator
Resistor Values (Ω)
Calculated Results
Circuit Diagrams & Formulas
Series Circuit
R_total = R₁ + R₂ + R₃ + ...
Same current flows through all resistors
Voltage divides across each resistor
Parallel Circuit
1/R_total = 1/R₁ + 1/R₂ + 1/R₃ + ...
Same voltage across all resistors
Current divides through each path
Ohm's Law & Power Calculations
Voltage
V = I × R
Voltage equals current times resistance
Current
I = V / R
Current equals voltage divided by resistance
Power
P = V × I
Power equals voltage times current
Frequently Asked Questions
How do I calculate resistors in series?
In a series circuit, simply add all resistance values together: R_total = R₁ + R₂ + R₃ + ... The same current flows through all resistors, but voltage divides proportionally across each resistor.
How do I calculate resistors in parallel?
In a parallel circuit, use the reciprocal formula: 1/R_total = 1/R₁ + 1/R₂ + 1/R₃ + ... All resistors have the same voltage across them, but current divides through each path.
What is Ohm's Law?
Ohm's Law states that voltage (V) equals current (I) times resistance (R): V = I × R. This fundamental relationship allows you to calculate any one value if you know the other two.